Like MRTCAT we have gone the Bill Fitzmaurice route and couldn't be happier. 2 x Otop 12s and 2 T39s, indoors, outdoors, tiny pubs, theatres, infact anywhere. We run it crossed over 3 way with a pair of these, http://www.thomann.de/gb/the_tamp_d4500.htm, one either side. Brilliant sound and brilliant volume if needed. The mixer and all outboard gear is racked and on wheels and sits in the backline so I can get at it easily and we only have to run a mains lead, 2 signal leads to the amp racks and 2 foldback speaker leads and we're ready to go.
I have to admit that I'm not a fan of Mackie systems, they sound a bit harsh to me.